/* ============================================================
   Text2TactileGraphics Project Page
   ============================================================ */

:root {
    /* ---------- palette ---------- */
    --stone-50: #fafaf9;
    --stone-100: #f5f5f4;
    --stone-200: #e7e5e4;
    --stone-300: #d6d3d1;
    --stone-400: #a8a29e;
    --stone-500: #78716c;
    --stone-600: #57534e;
    --stone-700: #44403c;
    --stone-800: #292524;
    --stone-900: #1c1917;
    --stone-950: #0c0a09;
    --amber-50: #fffbeb;
    --amber-100: #fef3c7;
    --amber-200: #fde68a;
    --amber-300: #fcd34d;
    --amber-400: #fbbf24;
    --amber-500: #f59e0b;
    --amber-600: #d97706;
    --amber-700: #b45309;
    --amber-800: #92400e;
    --amber-900: #78350f;
    --amber-950: #451a03;

    /* ---------- Bootstrap theme colors ---------- */
    --bs-body-color: var(--stone-800);
    --bs-body-color-light: var(--stone-700);
    --bs-body-color-dark: var(--stone-900);
    --bs-body-bg: var(--stone-50);
    --bs-body-bg-variant: var(--stone-100);
    --bs-muted: var(--stone-600);
    --bs-secondary-color: var(--bs-muted);
    --bs-stroke: var(--stone-400);
    --bs-stroke-muted: var(--stone-200);
    --bs-primary: var(--amber-600);
    --bs-primary-dark: var(--amber-700);
    --bs-accent: var(--amber-400);

    /* ---------- Swiper theme colors ---------- */
    --swiper-theme-color: var(--bs-primary);
    --swiper-pagination-bullet-inactive-color: var(--bs-stroke);
    --swiper-pagination-bullet-inactive-opacity: 0.4;

    /* ---------- fonts ---------- */
    --bs-font-sans-serif: "Source Sans 3", system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", "Noto Sans", "Liberation Sans", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
    --bs-font-serif: "Source Serif 4", serif;
    --bs-font-monospace: "Source Code Pro", SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    --bs-body-font-family: var(--bs-font-serif);
    --bs-body-line-height: 1.6;

    /* ---------- shadows ---------- */
    --bs-box-shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    --bs-box-shadow: 0 0.25rem 0.75rem rgba(0, 0, 0, 0.1);
    --bs-box-shadow-lg: 0 0.375rem 1rem rgba(0, 0, 0, 0.15);

    /* ---------- transitions ---------- */
    --transition: .15s ease;
}

/* ---------- base ---------- */
h1, h2, h3, h4, h5, h6 {
    color: var(--bs-body-color-dark);
    font-family: var(--bs-font-sans-serif), sans-serif;
}

/* ---------- buttons ---------- */
.btn {
    --bs-btn-padding-x: 1.25rem;
    --bs-btn-padding-y: .5rem;
    --bs-btn-font-family: var(--bs-font-sans-serif);
    --bs-btn-font-size: .9rem;
    --bs-btn-font-weight: 600;
    --bs-btn-border-radius: var(--bs-border-radius-pill);
    box-shadow: var(--bs-box-shadow-sm);
    transition: color var(--transition), opacity var(--transition), background-color var(--transition),
    border-color var(--transition), box-shadow var(--transition), transform var(--transition);
}

.btn:hover, .btn:focus {
    transform: translateY(-1px);
    box-shadow: var(--bs-box-shadow);
}

.btn:focus-visible {
    outline: 2px solid var(--bs-primary);
    outline-offset: 0;
}

.btn:active {
    transform: none;
    box-shadow: var(--bs-box-shadow-sm);
}

.btn-tactile {
    --bs-btn-bg: var(--bs-body-color);
    --bs-btn-active-bg: var(--bs-body-color);
    --bs-btn-hover-bg: var(--bs-body-color-light);
    --bs-btn-color: var(--bs-body-bg);
    --bs-btn-active-color: var(--bs-body-bg);
    --bs-btn-hover-color: white;
    --bs-btn-border-color: var(--bs-muted);
    --bs-btn-active-border-color: var(--bs-muted);
}

.btn-tactile-light {
    --bs-btn-bg: var(--bs-body-color-light);
    --bs-btn-active-bg: var(--bs-body-color-light);
    --bs-btn-hover-bg: var(--bs-muted);
    --bs-btn-color: var(--bs-body-bg);
    --bs-btn-active-color: var(--bs-body-bg);
    --bs-btn-hover-color: white;
    --bs-btn-border-color: var(--bs-muted);
    --bs-btn-active-border-color: var(--bs-muted);
}

.btn-tactile-outline {
    --bs-btn-bg: var(--bs-body-bg);
    --bs-btn-active-bg: var(--bs-body-bg);
    --bs-btn-hover-bg: var(--bs-body-bg);
    --bs-btn-border-color: var(--bs-stroke);
    --bs-btn-active-border-color: var(--bs-stroke);
    --bs-btn-hover-border-color: var(--bs-body-color);
    --bs-btn-disabled-opacity: 0.2;
}

.btn-square {
    --bs-btn-padding-x: .7rem;
    --bs-btn-padding-y: .3rem;
    --bs-btn-border-radius: var(--bs-border-radius);
}

.btn-circle {
    width: 2.5rem;
    height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}

/* Compact download button beside each gallery pane label */
.gallery-dl.btn-circle {
    width: 1.9rem;
    height: 1.9rem;
    flex: 0 0 auto;
    padding: 0;
}

/* ---------- hero ---------- */
.hero-heading {
    font-weight: 800;
    letter-spacing: -.02em;
    line-height: 1.15;
    margin: 0 auto;
    text-wrap: balance;
}

.subtitle {
    font-family: var(--bs-font-sans-serif), sans-serif;
    font-weight: 600;
    letter-spacing: -.01em;
}

/* ---------- authors ---------- */
.authors {
    font-family: var(--bs-font-sans-serif), sans-serif;
    font-weight: 600;
    letter-spacing: -.01em;
    line-height: 1.7;
}

.author-link {
    color: var(--bs-body-color);
    text-decoration: none;
    transition: color var(--transition);
}

.author-link:hover,
.author-link:focus {
    color: var(--bs-primary);
    text-decoration: underline;
}

.authors sup {
    font-weight: 500;
    color: var(--bs-muted);
}

.affiliations {
    font-family: var(--bs-font-sans-serif), sans-serif;
    font-weight: 500;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.25rem 1.75rem;
}

.affiliations sup {
    margin-right: .1em;
}

.footnote {
    font-family: var(--bs-font-sans-serif), sans-serif;
    font-size: .85rem;
}

/* ---------- section generics ---------- */
section {
    padding: 4rem 0;
}

@media (max-width: 575px) {
    section {
        padding: 3rem 0;
    }
}


section + section {
    border-top: 1px solid var(--bs-stroke-muted);
}

.section-title {
    font-weight: 800;
    margin-bottom: 1.5rem;
}

.section-title::after {
    content: '';
    display: block;
    width: 3rem;
    height: 2px;
    background: var(--bs-primary);
    border-radius: 2px;
    margin-top: .4rem;
}

/* ---------- gallery ---------- */
.swiper-pagination {
    width: auto !important;
}

.swiper-pagination-bullet {
    transition: opacity var(--transition), background var(--transition);
}

.swiper-pagination-bullet:focus-visible {
    outline: 2px solid var(--bs-primary);
    outline-offset: 0;
}

.gallery-media {
    width: 100%;
    height: 340px;
    object-fit: contain;
    background-color: #252530;
    --poster-color: transparent;
}

.gallery-pane-label {
    font-family: var(--bs-font-sans-serif), sans-serif;
    font-size: 0.9rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .04em;
    color: var(--bs-muted);
}

.prompt {
    font-style: italic;
}

.prompt::before {
    content: '\201C';
}

.prompt::after {
    content: '\201D';
}

/* ---------- method ---------- */
.placeholder-img {
    width: 100%;
    height: 400px;
    background: repeating-linear-gradient(
            45deg,
            var(--stone-100),
            var(--stone-100) 12px,
            var(--stone-200) 12px,
            var(--stone-200) 24px
    );
}

/* pipeline steps */

.pipeline-step {
    background: white;
    border: 1px solid var(--bs-stroke-muted);
    border-radius: var(--bs-border-radius);
    box-shadow: var(--bs-box-shadow-sm);
    padding: 1.5rem;
    text-align: center;
    position: relative;
    height: 100%;
}

.pipeline-step .step-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    background: var(--bs-primary);
    color: white;
    font-family: var(--bs-font-sans-serif), sans-serif;
    font-weight: 700;
}

.pipeline-step .step-heading {
    line-height: 1.3;
    font-weight: 700;
    font-family: var(--bs-font-sans-serif), sans-serif;
    color: var(--bs-body-color-dark);
}

.pipeline-step p {
    color: var(--stone-500);
    margin: 0;
    line-height: 1.5;
}

/* clickable tab states (synced to method video) */
.pipeline-step[role="button"] {
    cursor: pointer;
    transition: border-color var(--transition), box-shadow var(--transition),
    transform var(--transition);
}

.pipeline-step[role="button"]:hover {
    transform: translateY(-2px);
    box-shadow: var(--bs-box-shadow);
}

.pipeline-step[role="button"]:focus-visible {
    outline: 2px solid var(--bs-primary);
    outline-offset: 2px;
}

.pipeline-step.active {
    border-color: var(--bs-primary);
    box-shadow: 0 0 0 2px var(--bs-primary), var(--bs-box-shadow);
}

/* responsive 16:9 YouTube embed (matches visual-tactile-synthesis.github.io) */
.video-container {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    max-width: 100%;
    background: #000;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

/* ---- TL;DR teaser caption (full width, matches the video below) ---- */
.tldr {
    line-height: 1.5;
}

.tldr-label {
    font-family: var(--bs-font-sans-serif), sans-serif;
    font-weight: 700;
    color: var(--bs-primary-dark);
}

/* ---------- bibtex ---------- */
.invert-colors {
    background: var(--bs-body-color);
    color: var(--bs-body-bg);
}

.copy-btn {
    position: absolute;
    top: .75rem;
    right: .75rem;
}

/* ---------- utility ---------- */
.font-sans-serif {
    font-family: var(--bs-font-sans-serif), sans-serif;
}

.text-muted {
    color: var(--bs-muted);
}

.bg-body-variant {
    background: var(--bs-body-bg-variant);
}

.subtle-gradient {
    background: radial-gradient(ellipse at 50% 0%, rgb(from var(--bs-primary) r g b / 10%) 0%, transparent 75%);
}

.max-w-reading {
    max-width: 720px;
}

.max-w-image {
}

.border-muted {
    border-color: var(--bs-stroke-muted);
}

/* ---- Accessible 3D model: keyboard hint + text description ---- */
model-viewer:focus-visible {
    outline: 3px solid var(--bs-primary);
    outline-offset: 2px;
}

#gallery kbd {
    font-size: 0.75em;
    padding: 0.1em 0.4em;
    margin: 0 0.1em;
}